


Pleasurable Experiments

by midnightmuser



Category: Sonic the Hedgehog - All Media Types
Genre: Anal Sex, M/M, Multiple Penetration, Oral Sex, Tentacle Dick, Tentacle Sex
Language: English
Status: Completed
Published: 2016-10-16
Updated: 2016-10-16
Packaged: 2018-08-22 18:49:09
Rating: Explicit
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 4,126
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/8296324
Author URL: https://archiveofourown.org/users/midnightmuser/pseuds/midnightmuser
Summary: Knuckles is lately plagued by visions and dreams leaving him wanting and lustful. Luckily, a little surprise from Tikal reveals a certain ancient watery beast is also eager for some naughty fun.





	

**Author's Note:**

  * Inspired by [Experimentation 2](https://archiveofourown.org/external_works/234568) by Gree Falcon. 



> This is project long in the making that I finally got done thanks to some much appreciated creative input.

The sun was warm over the floating space known as Angel Island. It bathed the clearings in bright light, even with the cooler temperatures from being about a mile or so off the ground. The Red Mountains cast dramatic shadows over the landscape, providing some protection if necessary. It was alive with activity, as it was every day, from the shifting sands of Sandopolis to the vibrant Mushroom Hill.  
  
In a more isolated section of the island, sitting at the base of a flight of steps that went up to a massive, glowing green emerald, was the shrine’s guardian, Knuckles the Echidna. The red-furred male was meditating quietly, gloved hands draped over his lap and his legs crossed. His eyes were closed, his breathing steady as if in sleep. It was a ritual he’d performed countless times. Shut out all noises and sounds, and focus on his breathing.  
  
His mind emptied, opening it to the energies of the Master Emerald and the island. It was silent and tranquil. Colors formed in the otherwise black expanse, showing the way the energy moved throughout the expanse. He allowed himself to relax and watch them dance the way nature intended.  
  
The energy within himself was like an orange light bulb in his belly, flowing out like tiny rivers to his hands and feet and head. It pulsed in time with his heartbeat, ensuring everything flowed correctly. He was in tune with nature… he was…  
  
‘Aw shit, not again…’ The echidna huffed and broke his link, realizing he’d gotten hard again. Chaos, he had to look like an idiot, sporting a dripping erection while he was meditating… “Dammit,” he opened his eyes and stared down at his dick. “Why the hell am I getting so horny so often anymore…?”  
  
It was a rhetorical question, but he still couldn’t help but ask it. Lately, he’d been swarmed by arousing fantasies, often times when he was trying to meditate and think of nothing at all. Wet dreams, Sonic had explained when he first started having them. The hero was a bit awkward at explaining it, but he got the gist.  
  
“My hormones are telling me to mate… But why now? Why so frequent? Especially with no other echidnas around?”  
  
Well, his dreams didn’t involve members of his own species, but that was a moot point… All he knew was that it left him even more frustrated than usual until he ‘took care’ of things… Grumbling, he started to stroke his long, thick shaft with his gloved hand, letting the texture stimulate him. “Aaah… Oh yeah…”  
  
Part of what made it so embarrassing, but just so fucking _good_ , was his instincts. He really tended to get into it, panting and snarling like a feral beast when he got closer to release. In no time, he was rutting into his hand, instinctively bucking up and down. Pre-cum slicked his glove, his cock throbbing madly. His thumb rubbed over the oozing slit, and he shuddered at the sensation. He fucked his hand, faster and faster, leaning his head back while he growled in rapture. “Anh! Nngh, ffffuuuck!!” A thick jet of cum spurted out onto the grass, painting it milky white.  
  
The Guardian relaxed once his arousal was taken care of for the moment, wiping his wet glove off. He was a bit more grateful when he shot on the ground rather than his own chest like he did when waking up from a wet dream.  
  
Still, he hated that it was happening so much. Seriously, why?  
  
A soft noise off in the distance sounded, and the red-furred mammal shot to his feet. “Who’s there?!” he barked, demanding to know the identity of his intruder. Sonic and Tails always called… It was probably Rouge. With a growl, he took off for the source of the noise. It was infrequent, but it sounded like a soft, repetitive cracking noise. Like a small landslide or something. The more he traversed the small mountains, the louder it became, until he saw that decently-sized boulders were tumbling off one of them, chipping away at the huge pile at the base.  
  
Slowly, he realized that as dust faded, there was a hole. A secret tunnel was hidden in the mountains. His curiosity piqued, he waited for the landslide to stop, then stepped inside. It was dark, as expected, but he could already tell there was something unusual about this spot. He kept his hands on the wall, feeling around, until he could feel a torch.  
  
“Bingo.” So this _was_ something that his ancestors had used… A previous landslide had just blocked it off, and he’d been none the wiser. He had to laugh a bit. Knuckles focused his energy into the dead material in the torch, relighting it so he could more accurately see what lied within the depths. He’d never realized how much of his history was still on the island, as most of it was lost to the rainforest back in the Mystic Ruins. But why was this area so out of the… way…?  
  
Purple eyes widened as he noticed a set of murals. It was a picture of one of the echidnas, wearing a fancy necklace that depicted him as a chief. But what really drew his attention was the sequence of images that involved said chief.  
  
“It’s a ritual,” he said out loud. But it was hardly the usual dance, or even the morbid blood rituals like he’d seen on TV down on the surface. Instead, it was a massive orgy of some kind, with the chief in center. His cheeks flushed deeply, but he was hardly embarrassed. Shocked, yes, but not embarrassed. He found it intriguing and arousing, as the expressions depicted all of them having a rather good time.  
  
“Wait. The chief is…” He started noticing the runes that accompanied the images. “It’s just a… a party? They’re not even doing it to worship anything? Just… for fun?” That was interesting. He continued to follow, stroking softly at his sheath with a gloved hand. “Wait a sec… that image is…” He almost squeezed his crotch out of reflex, noticing one of them showed the chief himself was bent over, happily getting railed by an echidna with a really thick member while he was inside another pleasured male. “Holy shit…”  
  
To fuck and get fucked… he felt heat sear his cheeks. Chaos, who knew his ancestors were so damn _raunchy_? But it did explain why often times his lewder dreams would involve him either with Sonic, Shadow, or between both at once in a hot threesome that would leave him soaked come morning.  
  
‘Your sexual drive is potent, Guardian…’ a soft, feminine voice echoed in his ear. Knuckles smirked.  
  
“Hey, Tik,” he said with a soft chuckle, brushing some of the dust off the murals. “Guess you led me here?”  
  
‘Hee hee! Always the detective… Yes… It’s hard to ignore the aftermath of your dreams… you’re quite loud.’  
  
Knuckles blushed but laughed, realizing that he was in an atrium. “Is this where these orgies happened or something?” Of course, it was barren, probably having lacked in use since four-thousand years ago. But it only made sense for why it was even here.  
  
‘Indeed.’ The female’s spirit explained. ‘I could tell you’ve been curious… And thought you should know you are not alone.’ Knuckles smiled as he took a look around.  
  
“Yeah… I mean, I know I’m the last, but… it’d be nice to have a little fun up here, I guess… But I don’t think Sonic and Shadow swing that way.”  
  
‘I have my doubts as well… But…’ she materialized like a ghost, giving him a soft and obviously telling smile. ‘…There is someone who wishes to experience pleasure as well. And unlike me, is not stuck in an immaterial form.’  
  
Knuckles rose an eye-ridge for a moment, before his mind rolled into the gutter. “You mean… Chaos wants t-to… Chaos wants to fuck me?” The more he thought about it, the more he wondered why he’d never considered it. Chaos could shape shift to make any position he’d think of! He could literally fuck him anywhere!  
  
Tikal nodded with a soft giggle. ‘Yes, he’s wanted to have some fun with you for a while now. Now that he’s not so angry, he’s become… quite enamored with the idea.’  
  
Knuckles grinned. “Well, if my ancestors were up to things like that,” he jerked his thumb back to the hall with the murals, “I think messing around with Chaos would be a lot of fun.”  
  
\----  
  
It was about midday when Knuckles returned to the altar, having paused to check around the area. He still had plenty of traps to protect the emerald, and wanted to ensure they were still in working order. By then his arousal had cooled, but it wouldn’t take long to get back up. “Hey, Chaos! You around?”  
  
About ten seconds later, a soft light rippled from the emerald, and Chaos stepped out of it. Solid green eyes looked directly at him, though it was less of seeing it and more like he could feel the other’s gaze. He had to admit, Chaos was… kinda cute. Perhaps it was because he used to be a simple, everyday Chao, or it was just his own weirdness of finding a four-foot tall, blob handed, two-toe-footed, solid-eyed creature with a visible brain cute.  
  
Chaos cocked his head in slight confusion at Knuckles’ presence, before letting out a churr when the echidna started massaging his crotch. “So… Tikal tells me you wanna fuck.” The god perked up and nodded with a happy gurgle, and Knuckles pointed to the grass below and smirked. “Then I suggest you lie down.”  
  
The alien-like being heeded Knuckles’ advice. Eons of keeping to himself until Tikal’s arrival left him rather ignorant of mating practices… All he really knew was that it felt really good based off of Knuckles’ noises from his dreams.  
  
Once he was settled, he spread his legs and kept his arms to his sides. Knuckles approached the beast with eager steps, his cheeks turning pink and his cock sliding out of his sheathe. Chaos watched in intrigue and awe. He’d seen the Guardian’s erection before, several times, but now it was going to be much closer and even more intimate… Knuckles himself was equally excited. He was really going to have sex! Seeing those murals had made him very eager to indulge, and Chaos was just so _fuckable_.  
  
“Alright… now let’s get started…” Knuckles murmured. He recalled his memory from the somewhat dirtier flicks he’d seen on the surface, as well as his own dreams. “Can you suck?”  
  
Chaos nodded happily, supporting himself on his arms while Knuckles straddled his chest. Gently, the god slipped his lower face over the shaft, pulsing the gelatinous fluid around it. He still had memories of having a throat as a simple chao, and applied that to the blowjob. He sucked and slurped on Knuckles’ erection, getting it hard and throbbing, purring as he felt those gloved hands rubbing over his ‘skin.’  
  
The coolness of the watery flesh along with the fierce sucking had Knuckles going into spasms. “A-Ah! Oh shit…!” Panting softly, he started to thrust into Chaos’ mouth, which earned a soft groan from the horny creature. He started to leak into Chaos’ flesh, and though Chaos had no taste buds, he seemed to enjoy the slightly sticky warmth of it. Though just as he was getting into it, Chaos pulled off and went flat on his back. He curled a hand in a ‘come get it’ gesture, surprising him. Where did Chaos learn to do that?  
  
‘Guess it doesn’t matter…’ he idly, thought, getting down in between his legs. Those hips had his name on them, and he intended to collect. Thankfully, he didn’t need to worry about stretching or pain, so he pushed right in, grinning and moaning at the feeling. It felt the same as his mouth, but the position felt just so much naughtier and better. His cheeks were nearly as red as his own fur, something that Chaos burbled happily at.  
  
Slowly, he started to move. The insides of Chaos’ body moved and washed over him, providing a firm but gentle pressure that completely molded to his cock, making it an exact fit no matter how much was inside. He couldn’t help but shiver at that little aspect. Chaos was literally giving him the perfect adaptable entrance to fuck! He worked himself into a good rhythm, each thrust solid and smacking softly into Chaos’ body. Chaos churred and gurgled in pleasure, amazed at just how great it felt. He had no prostate, no sweet spot, but the mixing of their energies and the friction was just utter euphoria! He wished he could return the favor…  
  
Evidently, the Guardian was able to pick up on that, as he chuckled. Chaos would have blinked if he had eyelids. He returned his focus to the lustful purple eyes. Knuckles grinned down at Chaos as he slid his cock through the watery pelvis. “You can still fuck me while I’m doing you, y’know… You can use tentacles, right?”  
  
Chaos made a noise of excitement, starting to morph his hands, before Knuckles shook his head. He blushed a bit, but knew Chaos didn’t have reservations. “Don’t use your hands. Fuck me with your toes.” As if to demonstrate, he placed his hands over Chaos’ arms, holding them down while they joined.  
  
With almost a churr, Chaos elongated the two toes on his feet into long, prehensile tentacles, slipping one into the echidna’s body and drawing out a groan. “ _Yes_ …!”  
  
Knuckles started to thrust, moving his hips back and forth to slide his cock through Chaos’ body. Both of them groaned in pleasure, though Chaos had no blood to flush with. The only way Knuckles could see he was pleasured was due to the way he shivered and whined. Chaos returned the feeling by using one tentacle to lift Knuckles’ tail higher, shoving a second and then a third into his ass, spreading it wider to fuck him back. The echidna groaned deeply at the feeling of getting stretched, then howled when they started to move. They didn’t act in unison, instead each one acting on its own to triple-strike his insides over and over.  
  
Purple eyes gleamed happily, and he picked up the pace a bit in gratitude. His spines swayed with the motion, and Chaos gave soft bucks of his hips. The two stared at each other lovingly. It was so soothing, like they were surrounded by a balm despite the coolness of the bottom’s insides. Every touch was electric and stimulating, especially for Knuckles. His insides were touched, rubbed, and smacked just like in his dreams—no, it was better than his dreams. It was real, it was happening, and it wasn’t going to disappear.   
  
Chaos too seemed beyond overjoyed. Since the day he hatched, he’d never experienced something so amazing. Chao mating was hardly mating at all, instead more of a mix of their energies while they nuzzled. It felt good, but nothing, absolutely nothing could compare to the heat of the echidna’s dick in his insides.  
  
Red hips met translucent blue in repeated smacks, and Chaos’ head lolled around as the beast was pleasured at a level he could never have imagined. He wanted _more_! Concentrating on visualizing the shape of his lover’s erection, he started to form his own out of his torso, long and thick. Knuckles was only aware of it once it was near his mouth, and he shut his teeth once he saw just what Chaos wanted to try. “Too thick!” he said through them, but Chaos continued to wave the prehensile member about, rubbing his teeth and lips.  
  
He kept his mouth shut, letting out soft grunts and moans while he shifted his hips. His grip tightened on the gelatinous arms, forming indentations in the flesh. Each thrust was full and deep and fast, rocking the god’s form and making him moan. It sounded almost like someone blowing bubbles into a glass of water through a straw. In normal situations, it would probably be funny, but it was in response to pleasure, and it sent a lewd thrill through him.  
  
Chaos’ toes were smacking his prostate, sending jolt after fiery jolt through his body into his cock and his head, and he felt dizzy with pleasure. But as good as it felt, he was becoming more and more lustful as time went on. His craving for a good fuck was still missing something… Then he remembered Chaos had only used three tentacles. The fourth was still holding up his tail, something he couldn’t do himself due to its shape and structure.  
  
“Chaos!” he managed out through his teeth, eyes screwed shut in pleasure and effort. “More! Put the fourth in!” He pointedly bucked his hips up, trying to get that tentacle to move. But Chaos stayed put, almost as if teasing him. He tried to speed up in turn, hoping an increase in pleasure would entice him into returning the favor. He bucked, rolled, and ground his hips, but yielded no result, and his cock throbbed in need. Even after doing it until he’d tried everything he could think of, Chaos stuck to using his three. Sure, it felt good, but he wanted to feel _better_!  
  
Knuckles grunted as he tried to wiggle his ass and shake it off. “Nngh! C’mon!!” he growled through his teeth. Dammit, he wanted that fourth tentacle in him now! Chaos, though, seemed determined to keep it wrapped around his tail, and he grew more frustrated. “Fuck! Come on!” he shouted. “Get it in! Chaos, FUCK M-mmmph!!” In his verbal plea, he had forgotten about the cock poking at his lips, and it was now inside his mouth.  
  
Chaos let out a purr and started to piston his cock in his throat, making him grimace and gag with wide eyes. Thankfully, though, he did finally shove that fourth toe into his entrance, and he moaned around the cock. Slowly, Knuckles relaxed into it, and resumed moving. Even if Chaos was fucking him in two holes, he’d return the favor with better thrusts! He kept a good pace, even though occasionally he’d sputter from being unused to having something so massive moving up and down his throat. But he supposed that Chaos did deserve to get blown after getting him started…  
  
The chao tasted just like fresh spring water, cool, sweet, and refreshing. There was no earthy musk or tangy pre-cum, but in a way, it was better. It was as if he was literally bonding with an avatar of the planet! Having sex with nature itself… it made him so hard! Chaos seemed to smirk up at him amidst squeaks and gurgles, and then started to apply some extra pressure to his cock. Knuckles groaned and started to feel an orgasm starting. “Mmh…! Urk!”  
  
Chaos could tell, but instead of granting him release and relief, the beast sprouted a tiny tentacle from  his waist and tightened it around his balls, holding him back. Knuckles whined pitifully as he was forced to continue without reaching his peak. It just felt so damn good, why did he have to hold off?! He fucked him even harder, panting and gagging around his shaft. Drool began to drip from his chin and coated the appendage, which throbbed like a real cock. His eyes fluttered shut as he basked in the pleasure. It was so wet, so tight… He wasn’t even aware of Chaos’ hands turning into tentacles, slowly wrapping around his shoes and gloves…  
  
They fucked for several minutes, pre-cum constantly flowing into Chaos’ body while the real prize was constantly being held back. Knuckles moaned louder as the pain of being forced to not cum resulted in his arousal throbbing even more. It all just felt so good!  
  
Knuckles’ eyes shot wide as he heard a harsh ripping sound, then the feeling of cool air on his hands and feet. “Mmghh?!”  
  
He looked out of the corner of his eye to see his gloves had been torn away from his hands, his shoes ripped in half. He was completely, utterly naked, with Chaos’ tentacles in his ass and dick in his mouth. He stared at Chaos in shock, but the watery beast resumed heartily fucking him, and he began to moan in pleasure. Now he understood. Chaos didn’t just want to _fuck_ him, he wanted to _mate_ him. Shakily, he resumed thrusting into those cool, gelatinous hips.  
  
He could feel his lust growing stronger with each thrust thanks to his raging instincts. He slammed into Chaos and back onto those amazing tentacles. The echidna’s grip tightened around Chaos’ arms and he railed the beast with all he had. Chaos let out shaky gurgling wails, his back coming up off the ground in ecstasy.  
  
Knuckles purred at the sight of the powerful chao’s reactions. He almost wished Chaos could do more than make his adorable noises, but it was enough. Especially as Chaos’ tentacles began working faster, all four elongated appendages smacking his prostate repeatedly and the cock fucking his throat faster.  
  
He could feel his balls tightening again, and he let out a muffled groan around the thick girth in his mouth. “Mmmh… nnnnh…!” He began to shift into shorter, rapid thrusts, grinding his balls against his ass. He panted around Chaos’ throbbing dick and pushed deep, and Chaos slammed him hard, releasing the grip on his balls. His eyes shot wide and he let out a gurgled cry, his cock tingling before cum finally burst from his tip.  
  
His thick seed flowed into Chaos’ body, forming a ball of white that churned in the translucent torso. Chaos let out a churning groan, and an equal amount of water burst into his mouth and ass. To his surprise, it tasted faintly salty and sweet, like his own seed was giving it a bit of flavor. He groaned at the feeling of the fluid filling his insides and belly. The mutant chao stared deep into his hazy eyes, and Knuckles’ vision flashed. He saw Chaos under him, just as they were, but the creature’s body was no longer translucent blue, but instead a milky white.  
  
“Mmgh?!” he flushed deeply at the vision. The idea of Chaos’ body turning into cum was extremely hot… He dug his fingers deeper into his arms and bucked his hips even harder. Chaos squealed with bright eyes, as if surprised at his stamina, and fucked Knuckles deeper with his skilled appendages. Knuckles growled in lust and gave a few squeezes to Chaos’ arms.   
  
Chaos nodded in understanding, contorting his finger tentacles to start joining his toes inside the cherry red ass. Both chao and echidna howled as they entered, Knuckles screaming from being penetrated by the eight thin tentacles. His throat vibrated against Chaos’ cock, and the beast came hard again. The feeling of water flooding his body drew out another orgasm, filling Chaos with more warm cum. He moaned and screamed around Chaos’ dick, rutting into the water god, wanting more than ever to just cum and not stop. It just felt so good…!  
  
Chaos shoved more of his cock into Knuckles’ throat, driving his tentacles further through Knuckles’ ass, and the two rutted as hard and as long as they could. Knuckles watched his seed flow through his body, staining his legs and feet white, and soon he was getting fucked with tentacles of cum. Chaos’ orgasms seemed to just flow through him, as the only thing his belly did was bulge slightly with every thrust.  
  
Eventually, though, Knuckles felt his balls emptying completely, no longer able to produce cum of his own. He’d been totally milked by the chao, who looked as though would grin if he had a mouth. The tentacles slowed down, the thick cock slipping out of his mouth, and Knuckles coughed a bit at the influx of air. He looked at Chaos’ now blue and white body with pride. He pushed his muzzle against Chaos’ face, similar to a kiss, and the creature purred happily.  
  
“Heh… We’ll definitely have to do this again soon…” he said after a moment, standing up and helping Chaos to his feet. Chaos nodded, stepping back into the Master Emerald. He had plenty of water left, but he had grown tired as well, and decided to recharge. Knuckles looked down at himself and flushed as he saw diluted cum dripping down his thighs. “…Oh geez…” he hastily made his way to a nearby empty pond. Something told him, though, that he’d be using it more often if Chaos had anything to say about it...  



End file.
